Heya all, I've been using my Woodland Scenics rock molds for many years now and they are starting to get a little sticky. By this I mean that the rocks don't just pop out anymore - they have to be persuaded to leave the mold. I thought that if I took a toothbrush and cleaned out all the hydrocal residue real good that they would return to normal but that lasted just a couple times and they are back to being sticky again. Do you pre spray anything on your molds to help them release the hardened rock? And if so, does that affect the way the mold receives paint?